| 摘要 |
<p>1. A field effect transistor having a high cut-off frequency and comprising on a semi-insulating substrate (7) two access region called source region (10) and drain region (11) and a control region composed of a first active layer (8), a second layer (9) and a metal gate (12) called Schottsky-gate the second layer (9) being situated between the first layer (8) and the metal gate (12), characterized in that the semiconductor material of the first layer (8) which is doped at a rate of up to 10**16 atoms per cm**3 and which has a small forbidden band, constitutes together with the semiconductor material of the second layer (9), which is doped with at least 10**17 atoms per cm**3 and which has a larger forbidden band than the material of the first layer (8), an isotype n-n heterojunction, at the interface of which an electron accumulation zone on the side turned to the semiconductor with a small forbidden band (8) is formed, whereas an electron depletion zone is formed on the side turned towards the semiconductor with a large forbidden band (9), the thickness of the first layer (8) being equal to the thickness of the accumulation zone (about 0,1 mu m) and the thickness of the second layer (9) being equal to the thickness of the depletion zone (about 0,1 mu m), the semiconductor materials of the two layers (8, 9) presenting moreover the same cristal lattice parameter.</p> |
